Let’s say you have three email addresses set up on your domain: firstname.lastname@example.org, email@example.com, and firstname.lastname@example.org. So what happens to mail addressed to email@example.com? By default, email bound for “unknown names” will be discarded by the server. This is done to reduce massive spam loads (we sometimes see hundreds of messages per hour arriving for made-up addresses on customer domains).
If you prefer, you can have mail bound for “unknown names” routed to a known email account. In the Mail Management section of cPanel, look for the “Default Address” option. Set the default address to, say firstname.lastname@example.org and all mail that doesn’t match an existing address will be delivered to that mailbox.
Chances are, you’ll find that accepting mail bound for unknown names will get you a whole lot of spam and strange bounce messages. Birdhouse strongly recommends setting the Default Address option to:
Discard with error to sender
If you want to enable receiving of mail to a specific address, just create a mailbox or forwarder for it, and it will be excluded from the :fail: rules.